Standard-definition television (SDTV or STD) is a television system that uses a resolution that is not considered to be either high-definition television (720p, 1080i, 1080p, 1440p, 4K UHDTV, and 8K UHD) or enhanced-definition television (EDTV 480p). The two common SDTV signal types are 576i, with 576 interlaced lines of resolution, derived from the European-developed PAL and SECAM systems; and 480i based on the American National Television System Committee NTSC system. Standard definition television also provides a picture quality similar to VHS (Video Home System). SDTV and high definition television (HDTV) are the two categories of display formats for digital television (DTV) transmissions, which are becoming the standard. Some televisions also use STD.